Reno_XJ

Long time lurker first time poster. Jeep has long cranks before it starts if it sits for 1-2hrs or more unless I prime the system. I am going to drop the tank tomorrow when I have access to a shop and lift. What I am wondering is do i need the whole fuel pump assembly, or just the pump? I know the check valve in the 97+ is in the tank. Just dont know if i can get the $100 pump or if I need the $320 assembly. Its a 1997 4.0. Thank you

5-90

If it runs fine, but you've just isolated it to long crank times due to fuel delivery, you can get an inexpensive part from BMW and put it in the softline that exits the tank for rather less than you'd spend on the pump...

To isolate the fault, you'll want to turn the key to ON for five seconds or so before you try to crank it - you should be able to hear the pump run behind you. After a few seconds, turn the key to START and see if it kicks over straight away. If it does, it's the fuel check valve not retaining pressure. If it does not, the problem it elsewhere (faking CKP becomes likely at that point - it's not in a friendly environment.)

Also, while you have the tank down (if strictly necessary,) I'd measure out and see about putting in an access hatch in the cargo area, under the carpet. I used to do this when working on F-bodies, because dropping the tank was a pain (I just measured it out and made a template. Make the marks, use my Dremel to cut it all out, do the work, and set it all up so that it was a door for the next time. Took an extra hour or so to do in the first place - but R&I on an F-body fuel tank took about three, so that was already saving time! Knocked about four hours off of the job next time as well, and saved having to drain the damned tank. Once I'd done the fuel pump once, I could do the next one in about 30 minutes.)

I say "if strictly necessary" because the earlier XJs had the access port on the front of the upper half of the tank, not atop the tank. Have you checked just to make sure? Do that, and do the test I described above to further isolate the problem (you'll never kick yourself harder than you would if you did a bunch of work you found out you didn't have to do...)

victorlanda

5-90
what inexpensive part from BMW??

jomps

i got a 97+ fuel module assembly that was working when i pulled it if you want: could arrange a low price...and check pressure on fuel line...should spray out pretty good. if its weak and hissing air the check valve is not doing its job

tjwalker

The BMW check valve is NOT recommended for the fuel delivery system 97 and newer.
Older is okay as the design is completely different. The "return" system is much different. Don't try the check valve fix.

Drop the tank, replace the entire assembly while you are doing this. Unless you like doing things twice.

I recommend a Bosch fuel pump assembly. Stay away from Airtex, they have a big time reliability problem.

5-90

Ah - didn't know that. Thanks!

(So far, all of the XJs I've done extensive work on have turned out to be RENIX - I seem to be the local "RENIX Guru" for the area. I'm not complaining - but that does mean a few holes in my experience...)

Oh - and concur on the Bosch, although I've also used Carter with good results (and both used to OEM for TRW, bfore TRW got out of the parts biz...)

victorlanda

well, looks like there no fix for my 2001, i'm gonna look for a bosch fuel pump then.

mphilleo

I've got a 1990 XJ which that could be pretty handy for. Please, tell me more, sir...Are there any links with info on what part is required and how to install it?

5-90

Pillage around - I know it's been discussed on NAXJA in the past, and probably has a part number in the relevant thread.

You can also check with industrial/hydraulic supply houses, and see what you can find there. Many of them carry fuel-rated parts, including check valves, but specify that the part must be fuel-rated. The hose on the RENIX should be 5/16" ID, and a 5/16" hose barb will be what you want (it's the same size as the fuel filter, if you want to take that in to check.)

If you're unsure of any industrial/fluid power houses in your area, find a Parker-Hannifin dealer on their website (Google it,) and you should find one close enough to you.

tjwalker

Yes, NAXJA is the forum that has delved into this the most. I have seen some people with some success with the check valve on earlier models.

Here is a thread that explores why you shouldn't try a check valve though on your 1997.

http://208.101.10.250/~naxjaor1/foru....php?t=1012432